Organomercaptomethyl-silicon compounds and production



3,345,393 United States Patent ice PM 3,

3 345 393 m being equal to 1 or 2, wherein X denotes a chlorine ORGANOMERCAPT6METHYLSILICON atom or a lower alkoxy radical, with (2) an optionally hy- COMPOUNDS A PRODUCTION droxyl-substituted monoor polyvalent mercaptan includ- Walter Simmler, Cologne-Mulheim, and Hans Niederhlg thiophehels), in the Presence of a tertiary hittepriim, Monheim, Germany, assignors to Farbenfabriken gen base and optionally an inert solvent.

Bayer AhtiehfigesehsehaftsLevelkhsell, y, aGel" For carrying out the process, either a mercaptan is man corpqm mixed with ,at least the amount, stoichiometrically calcug g gg g gg 'g g ig g b fi ggg lated from the reaction equation, of 'a tertiary nitrogen p pp a n g base and optionally an inert solvent, gradually adding 5 Claims (Cl z69 448.z) 10 thereto, normally with heating, the bromomethyl-silicon compound which may likewise be diluted with a solvent,

The invention relates to silicon-organic thioether derivaor, inversely, the mercaptan amine mixture is gradually nvestcontammg the group added to the bromomethyl-silicon compound. Benzene :C S CH l 0 and its homologues are recommended as inert solvents. 2 T They serve for keeping the crystal mass formed by pre- 3 cipitation of salt sufiiciently stirrable. Their amount has as essential structural unit; moreover, the invention reto be chosen in accordance with this Purposelates to a process of producing these derivatives. In the ease of Polyvaleht mercaptans, it i$ essentially Compounds f h type are Substantially 1 1 and a question of the chosen molecular proportions, Whether arylmercaptomethyl-siloxanes, the other siloxane units of 0 HS groups remain free, leading, for example, to the groulh which may be selected in known manner from mono-, diihg 3 2 x y or Whether thio and tri-functional alkyl-siloxane and aryl-siloxane units. ether bridges Such as These siloxanes have the composition R SiO with a i H S C H S CI-I Si(CI-I numerical value of n between 1 and 3, and with the proviso that at least one of the substituents R is an organomercaptomethyl radical and all other radicals R are alkyl or aryl radicals which may also be substituted indifferently. Derived from polyfunctional mercaptans carrying two are obtained.

In the reaction of polyfunctional mercaptans which contain in the adjacent position to the HSC group a functional group, e.g. OH, capable of reacting with a silicon-func- 'functional groups in adjacent positions, six-nu b d tional siloxane substituent, six-membered heterocycles are heterocycles representing, for example, 2-silaand 2,6- formed; for p in one of the simphest Cases, disila-1,4-oxathiane derivatives, also belong to the thiocordin to ethers to be produced according to the invention. H H B OH S, OH 00 H C H N The invention is based on the discovery that bromo- 205 r k 1( m- 2 5 2 5h methyl-silicon compounds react directly and sometimes HOOZH" (CZHSMNHBT even at room temperature with mercaptans and, in the E20 Si presence of tertiary amines, yield the thioether derivatives 8; g in a smooth reaction, splitting off hydrogen bromide.

This discovery is the more surprising, as, in spite of the greater electron affinity of chlorine in comparison with It s fur h r n f nd t W n sing in th afor bromine, the analogous chloromethyl silicon compounds 4 described reaction instead of the ethoxysilane derivative,

HaC O CH I CHzCHzOH require the use of metal mercaptides for the same purpose, bromomethyl-dimethyl-chlorosilane, a side reaction takes and yet lower yields of sila-alkyl thioethers result even place, which leads with siloxane condensation to the forthen. mation of 1,4-dithiane and water, in which a sulphonium The use of a mercaptide involves not only the substansalt, i.-e. the bromide of 2,2,6,6-tetramethyl-2,6-disila-4- tial additional exppenditure for its preparation, but also (;3-hydroxyethyl)-l,4-oxathiane, is formed: the disadvantage that the mercaptide, being insoluble, must This oxathiane derivative is also obtained by carrying be reacted in a heterogeneous phase, and that it is hygroout the reaction according to the invention of li-hydroxyscopic as well as sensitive to hydrolysis so that water and ethlymercaptan directly with 1,3-di-(bromomethyl)- alkali metal hydroxide penetrate into the reaction mixture 1,1,3,3-tetramethyl-disil0xane. Thus, also in this case ring leading to substantial side reactions of the silicon comformation occurs as well as the formation of the sulphopounds. niurn cation.

According to the invention therefore organomercaptomethyl-silicon compounds are produced by reacting (1) HOCHTHZCSH BrCH2'Si(CHH)TOSKOHK)TCHZBr (czHthN-i a bromomethyl silicon compound which may be (a) an organopolysiloxane of the general formula R SiOH/Q H3GS|i Sl-CHs with a numerical value of n between land 3 and wherein C H HB H at least one of the siloxane units has the formula 5 t mN I to S Br BI'CHg-Si O3 /2 z 2 in being equal to 1 or 2, and every other R denotes an optionally indifferently substituated alkyl or aryl radical, or (b) a bromomethyl-silane of the general formula The preponderantly new alkyland aryl-mercaptosili con compounds produced according to the invention are especially suitable as lubricants and for the modification BrCH Si---(CH ),,,X of polymers.

a The following examples are given for the purpose of illustrating the invention.

Example 1 A solution of 160 g. (0.5 mol) of 1,3-di-(bromomethyl)-1,1,3,3-tetramethyl-disiloxane in 100 cc. of toluene is added dropwise in the course of 2 hours while stirring and slowly heating to 100 C., to a mixture of 90 g. (1 mol) of n-butylmercaptan, 121 g. (1.2 mols) of triethylamine and 300 cc. of toluene, and stirring is continued at 100 C. for a further 8 hours. The precipitated salt is separated by filtration. It contains 71.1 g. of bromine, determined by titration after dissolution in water, and corresponding to 89 percent of the theoretically possible amount.

The filtrate thereof is concenarated by evaporation with evacuation by means of a water jet pump, the residue is again filtered and the filtrate distilled. As main fraction boiling between 2 and 3 mm. Hg at temperatures between 130 and 150 C., 1,3-di-(n-butylmercaptomethyl)- 1,1,3,3-tetrarnethyldisiloxane is obtained in the form of a yellowish oil of refractive index 11 =1.4718. The yield of 98 g. amounts to 58 percent of the theoretical. Contents per weight according to elementary analysis: 48.3% C., 19.0% S (calculated for C H OS Si 49.6% C, 18.9% S).

Example 2 A solution of 160 g. of 1,3-di-(bromomethyl)-1,1,3,3- tetramethyl-disiloxane in 100 cc. of toluene is added dropwise in the course of 2 hours, while stirring, to a mixture of 110.2 g. of thiophenol, 121 g. of triethylamine and 500 cc. of toluene, whereupon the mixture slowly warms up and a white salt precipitates. Stirring is continued with heating at about 50 C. for a further 3 hours, the precipitated triethyl ammonium chloride is then separated by filtration which after washing with toluene and drying amounts to 162 g. It contains 43.4 percent by weight of ionic bromine (calculated 43.9).

The filtrate is first evaporated with evacuation by means of a water jet pump and finally evaporated to dryness 100 C. 3 mm. Hg. After removal of small amounts of further precipitated salt by renewed filtration, 183 g. of a yellowish oil of refractive index n =1.5615 are obtained, corresponding to 96.6 percent of the theoretically possible amount of 1,3-di-(phenylmercaptomethyl)- 1,1,3,3-tetramethyl-disiloxane. Contents per weight according to elementary analysis: 55.5% C, 16.1% S (calculated for C H OS Si 57.1% C, 16.9% S).

Example 3 1052 g. of a methylbromomethyl-polysiloxane having a bromine content of 11.5 percent by weight and the composition Si(CH )O 2,1Si(CH O.

is slowly added dropwise, while stirring, to mixture of 182 g. (1.65 mols) of thiophenol, 182 g. (1.8 mols) of triethylamine and 600 cc. of toluene. The reaction mixture is then heated at 100 C. for 3 hours and filtered. The salt remaining on the filter contains 87.5 percent of the bromine used. The solvent is distilled ofr from the filtrate, the residue is heated at 100 C. and at 2.5 mm. Hg and filtered. A viscous yellowish oil of refractive index n =1.4491 results as filtrate, in a yield of 950 g. corresponding to 87 percent of the theoretically possible amount of w,w',w"-tris-(phenylmercaptomethyl)-polymethylsiloxane of the formula wherein the numerical values of a, b and 0 amount to about 7 and their sum is 21.

Contents by weight according to elementary analysis: C, S (Calculated for C7gH16 O24S3Si 5Z 38.4% C, 4.4% S).

Example 4 98.6 g. (0.5 mol) of dimethyl-(bromomethyl)-ethoxysilane are added dropwise at 50 C. in the course of 3 hours, while stirring, to a solution of 39.1 g. (0.5 mol) of B-hydroxyethylmercaptan and 50.6 g. (0.5 mol) of triethylamine in 400 cc. of toluene, the reaction mixture is allowed to stand at room temperature for 10 hours and the precipitated triethyl ammonium bromide containing part of the ethanol formed in the reaction is then filtered off with suction; 97 percent of the theoretically possible amount of bromide can be titrated in its aqueous solution.

The residual ethanol and toluene are distilled off from the filtrate, whereupon salt again precipitates which is separated by filtration. The thinly liquid yellowish oil obtained as filtrate is fractionally distilled, and at 41 C./ 2.2 mm. Hg there are obtained 34 g. of a fraction having refractive index n =1.4800 and consisting of 2,2- dimethyl-Z-sila-1,4-oxathiane. Contents by weight according to elementary analysis: 40.2% C, 8.1% H, 21.4% S (calculated for C H OSSi: 40.5% C, 8.15% H, 21.6% S).

Example 5 A mixture of 78 g. (1 mol) of fl-hydroxyethylmercaptan and 101 g. (1 mol) of triethylamine is added dropwise in the course of 6 hours, while stirring, to a solution, cooled with ice, of 187 g. (1 mol) of bromomethyl-dimethyl-chlorosilane in 1 litre of benzene. The precipitated triethyl ammonium halide is then filtered otf with suction, in its aqueous solution 49 percent of the halogen used can be titrated. The filtrate is evaporated and a crystal mass again precipitates. The liquid is filtered off with suction, the crystals are washed first with benzene, then with ether, and finally purified with ether in an extraction device. The sulphonium salt formed in the reaction remains behind in the form of 42 g. of white lustrous leaflets consisting of the bromide of 2,2,6,6-tetramethyl-2,6- disila-4- (,B-hydroxy-ethyl -1,4-oxathiane.

Contents by weight according to elementary analysis: 30.29% C, 6.75% H, 10.35% S, 25.05% Br (calculated for C H O SSi Br: 30.26% C, 6.67% H, 10.10% S, 25.18% Br).

Example 6 Equimolecular amounts of 1,3-di-(bromomethyl)-1,1, 3,3-tetramethyl-disiloxane, p-hydroxyethylmercaptan and triethylamine are mixed, twice its volume of benzene is added and the mixture heated under reflux at boiling temperature for 8 hours. The same sulphonium bromide is obtained as according to Example 5, in admixture with the equimolecular amount of triethyl ammonium bromide, in almost quantitative yield.

Example 7 1 kg. of a methylbromomethyl-polysiloxane having a bromine content of 15.85 percent by weight and corresponding approximately to the formula is dissolved in 1 litre of o-xylene, the solution is heated under reflux at boiling temperature for 8 hours, while adding dropwise a mixture of 154 g. of fi-hydroxyethylmercaptan, 220 g. of triethylamine and 200 cc. of o-xylene. Heating with stirring is continued for a further 18 hours, the precipitated triethyl ammonium bromide is filtered off and the filtrate freed from o-xylene by evaporation and blowing out with nitrogen at C. and 50 mm. Hg. As reaction product there remains a polydimethyl-siloxane with fl-hy-droxyethyl-mercaptomethyl groups at the chain ends, as a yellowish oil with refractive index n =1.4272 and a viscosity of 73 cst. at 20 C.

Example 8 is then diluted with 100 cc. of toluene, and this solution is added dropwise in the course of 2 hours to a mixture consisting of 55 g. (0.5 mol) of thiophenol, 52 g. (0.5 mol) of triethylamine and 200 cc. of toluene. The reaction mixture is further stirred at 80 C. for 2 hours and then filtered and Washed with toluene. 91 percent of the bromine used are found in the filter residue by titration.

The filtrate is evaporated with evacuation, heated at 100 C. and 3 mm. Hg and again filtered. 117 g. of a phenylmercaptomethyl-substituted a,w-bis (trimethylsiloxy)-polymethylsiloxane of the formula are obtained as a yellowish oil having a refractive index n =1.4605 and viscosity 65.8 cst.

We claim:

1. 1,3-di (n butylmercaptomethyl) 1,1,3,3,-tetramethyldisiloxane.

6 2. 1,3-di-(phenylmercaptomethyl) 1,1,3,3-tetramethyldisiloxane.

3. oc,w-Di-(fl' hydroxyethylmercaptomethyl) dodecadimethyl-siloxane) 4. Organopolysiloxane of the formula 5. Organopolysiloxane of the formula References Cited UNITED STATES PATENTS 2,719,165 9/1955 Cooper 260-4482 2,960,492 11/ 1960 Morton et a1 260448.2 2,997,457 8/ 1961 Kantor 260--448.2 3,078,292 2/ 1963 Prober 260-4482 OTHER REFERENCES Cooper: J our. American Chem. Soc., vol. 76, July 20, 1954, pages 3713-3716.

Derwent: Belgian Report No. 81B, abstract of Belgian Patent No. 603,832, pub. Sept. 18, 1961, page A1.

Similar: Berichte der Deutschen Chemischen Gesellschaft, vol. 96, Jan. 21, 1963, pages 349-356.

TOBIAS E. LEVOW, Primary Examiner.

SAMUEL H. BLECH, HELEN M. MCCARTHY,

Examiners.

F. SHAVER, Assistant Examiner. 

1. 1,3-DI - (N - BUTYLMERCAPTOMETHYL) - 1,1,3,3,-TETRAMETHYLDISILOXNAE.
 4. ORGANOPOLYXILOXANE OF THE FORMULA
 5. ORGANOPOLYSILOXANE OF THE FORMULA 